Developers complaining that a company with a history of treating people poorly betrays them? Cry me a river.
In this case, I think it is more a failure in PR than anything else. Silverlight will continue to work on Windows and Mac, and it will be the primary way of writing apps for the Windows phone. MS has just publicly acknowledged that it's stupid to try to get the Silverlight VM to work on every stack of hardware / OS. They just did it in a very ham-fisted fashion.
That wasn't really news to anyone that's been paying attention anyway. We've been warning our developers away from writing any web apps with Flash or SL (except for video playback) for over a year now. You can write very capable, very pretty web apps using just javascript, CSS and HTML4. HTML5 just makes it that much easier.
This, right there. Silverlight isn't going away. It's still useful. They just aren't trying to compete in an area where it won't be as useful. However, Silverlight developers suddenly have this transferable skill that Flash developers don't have on the mobile side.
I currently contract for a company with 50,000 + employees and some pretty specialized software that way too many people need to access. Getting that to change is like turning a convoy of sea liners with no radio communication.
The programmers who actually understand the weird ass domain of that software really wish they were still writing COBOL on a mainframe, the users who know how to use the software are understandably reluctant to have to learn another application when the existing works fine for THEIR needs (and job security). We have succeeded in getting a lot of stuff transferred to Citrix servers, but there are still a few hold outs / problem areas.
So, yeah, sometimes we really need the existing old stuff to still work.
Which part of HTML5 are you talking about here? I always assumed that in this context HTML5 meant 'Canvas + <video> element'. I hope that developers aren't going to use Canvas to replace CSS/javascript menus, rounded corners etc. with Canvas-based ones 8(
Maybe I just don't know enough about Canvas and will it play nicer with the html/css separation model than Flash does, but from what I've seen so far I'm not getting my hopes up.